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# Getting to grips with nicotine strengths

Nicotine levels aren’t always displayed on e-liquid packaging in a way you recognize, especially if you’re new to vaping. Instead of amounts per mg, you’ll see nicotine percentages instead. Both are good ways of measuring, but unless you understand them of course, or how to convert them, you’re in a predicament. In this post, we’re going to clear up the confusion so you can work out just how much nicotine is in each of your purchases.

Nicotine in mg/ml form

The most common way of labelling e-liquid nicotine strengths is via the mg/mL measure – or milligrams per milliliter. Hence, there’s a certain amount of nicotine in each mL of your e-juice. A 10mg/mL bottle would contain 10mg of nicotine per mL, while a 15mg/mL bottle would contain 15mg nicotine per mL, and so on and so forth. To establish the total amount of nicotine in the bottle, multiply the milligram figure by the total number of millileters in the bottle.

Consider the 10mg/mL bottle once again. If the bottle was sized at 10mL, then the total nicotine content of the bottle would be 100mg (10mg x 10mL).

Nicotine in percentage form

Many prefer nicotine content described as a percentage for convenience. There’s no complicated math to work out here, you can tell just how much nicotine is in the bottle from reading the label – it may be low at 0.5 percent, or higher at 2 percent.

Therefore, if you have a 2 percent nicotine bottle, then as you’d expect, 2 percent of the bottle’s total contents would be nicotine – the rest would be a combination of PG, VG or both, along with any flavorings.

This method, known as “nicotine by volume”, works in the same way as alcohol percentages (ABV) – perhaps why people prefer it. That’s why you may see NBV on the bottle, meaning nicotine by volume. With e-juice, nicotine content is worked out in millileters, although technically there’s nothing stopping you working it out via mass.

How to make mg/mL to percentage calculations, and vice versa

Believe it or not, there’s nothing tricky about making the calculation from mg/ML to percentages, and back again. Say you have a 10mg/mL juice, to work out the percentage, divide the 10mg figure by 10, leaving you with 1, hence a 1% e-juice. This can be done with all measures: 25mg/mL is equal to 2.5% e-juice, 40mg/mL to 4% e-juice, and so on.

To go back the other way, just multiply the percentage by 10 and that will give you your milligram figure – for a 1% e-juice, 1 multiplied by 10 equals 10mg, therefore 10mg/mL.

Why does this calculation work?

You won’t need a deeper understanding of that to calculate nicotine percentages and concentrations in e-juice. Now we’ll show you why this trick works.

If you’re a math boffin, then you might have identified that the mg/mL measurement is flawed since it uses both mass (mg) and volume (mL). The Chinese came up with this method, and on its own it’s fine, but when trying to establish a percentage, you must work with two volumes.

Thankfully, the calculation is made easier given the density of nicotine. At a density of 1.01 grams per cubic centimeter, nicotine almost has a round-number density – 1,010 mg nicotine would take up one millileter in volume.

Let’s go back to our hypothetical 10mg/mL e-juice, assuming the total bottle size is 10ml. We can deduce that in total there is 100mg of nicotine in the product, since 10 times 10 equals 100. That equates to 0.099ml of pure nicotine in the e-juice.

Now we’ve got the 0.099mL figure, we can find out the percentage by taking the nicotine’s volume and dividing it by the e-juice’s total volume, and multiplying by 100. Therefore, (0.099mL / 10mL) x 100 equals 0.99% nicotine. There’s no need for scrupulous accuracy here, so this bottle would be labelled as 1% nicotine.

That’s the precise calculation, but since nicotine’s density is extremely close to 1 gram per cubic centimeter, a rough estimate will bring you the same figure a manufacturer would, since they just round it up. So you can just multiply by 10 to get the mg/mL figure, or divide by 10 for the percentage. But it’s nice to know why it works!